At the time amplification of nucleic acids (DNA, RNA, and the like) and the fragments thereof (oligonucleotides, nucleotides, and the like) is performed, in tests that require quantitativeness, such as the analysis of gene expression levels, it becomes necessary to perform the amplification such that the ratio of the relative amounts of the respective nucleic acids can be known. Consequently, by using the real-time PCR method, and by using a device provided with a thermal cycler and a fluorescence spectrophotometer, analysis by electrophoresis is made unnecessary as a result of the generation process of the DNA amplification products in PCR being detected and analyzed in real time. Furthermore, as a DNA amplification method that performs amplification while maintaining the quantitativeness with respect to the ratio of the relative amounts of the DNA or RNA contained in the sample before amplification, the SPIA (Single Primer Isothermal Amplification) method is used. In the SPIA method, the linear DNA amplification method resulting from an isothermal reaction utilizing DNA/RNA chimera primer, DNA polymerase and RNaseH has become used.
The temperature control in such nucleic acid amplification houses a vessel formed from polypropylene or the like, that contains the necessary reagents, such as the aforementioned template DNA, primers, DNA polymerase, nucleotides, and reaction buffer solutions, within a block-shaped housing part of an isothermal device formed from a material such as aluminum, and by heating or cooling the metallic block-shaped housing part and waiting until the solution temperature becomes a uniform temperature distribution, it is made to perform heating or cooling isothermally or at a next temperature (Patent Documents 1, 2 and 3).
At that time, sealing of the vessel for performing the temperature control with a lid prevents the entry of contaminants from the exterior, prevents fluid leakage from the interior, and is particularly necessary in order to exclude the effect of the air and the air temperature as much as possible until the reaction mixture within the housing part is heated or cooled, and the solution temperature becomes a uniform temperature distribution.
Then, in the real-time PCR method and the like, which monitors the nucleic acids (DNA, RNA, and the like) that are amplified in real time by utilizing a fluorescent compound, it is necessary to observe the amplification during a temperature cycle. Consequently, with respect to a vessel sealed with a lid, it is necessary to open the lid in order to perform optical measurements, or to perform light measurements from the exterior through a transparent lid or side surface. However, the manual opening of the lid by a user is time-consuming, and becomes an obstacle toward the consistent automation of the processing. Furthermore, at the time the lid is resealed, there is a concern of contamination from making contact with the reaction mixture in the vessel interior. Moreover, at the time of the temperature control, even if the lid is attempted to be removed from the vessel, it is difficult to easily open the lid due to the lid becoming adhered to the vessel opening as a result of moisture, and there is a concern in that rapid processing can not be performed. At the time the lid is opened, there is also a concern of contamination occurring from the liquid attached to the inside of the lid dripping or splashing (Patent Document 4).
Furthermore, at the time of the temperature control, in a case where measurements of the interior of the vessel are performed from the exterior of the vessel, although there is a need to make the lid of the vessel transparent and to perform the measurements from the exterior, there is a concern of the interior of the lid becoming cloudy from condensation, and the measurements becoming difficult.
On the other hand, in order to perform nucleic acid amplification, as a precondition thereof, it becomes necessary to extract a small amount of nucleic acids from the sample and to perform processing of the nucleic acids as template DNA within the reaction vessel together with various reagents, primers, DNA polymerase, nucleotides, reaction buffers, and the like, manually or using various devices for example. Therefore, in the present state, researchers and technicians that are specialized with regard to nucleic acids are needed.
This situation is preventing the generalization of genetic analysis and the expansion of clinical applications in hospitals, and the like. Therefore, at the time of clinical use and the like, in order to prevent cross-contamination and to reduce user labor, and to easily perform from the extraction, the amplification, and further, by means of a measurement, the genetic analysis of nucleic acids, then in addition to the need for full automation which consistently automates steps from the extraction, the amplification, and further up to the measurement of nucleic acids, the miniaturization of the device, and the provision of an inexpensive, high-accuracy device are important.